The present invention relates generally to equipment for the sport of bowling and particularly to a finger grip insert for placement within a ball defined hole such as the insert type shown and described in my earlier filed application of the same title filed under Ser. No. 06/224,113 on Jan. 12, 1981 and now abandoned.
An application on a bowling ball finger grip insert was filed by the present inventor in the United States on Apr. 21, 1980 under Ser. No. 142,407 which application has now issued as U.S. Pat. No. 4,289,312 and discloses an insert having non-uniform wall thicknesses when viewed in transverse section.
By way of background bowling balls are, for the most part, made of hard rubber or a polyester resin. Further, a variation in ball material may exist between an outermost surface layer, approximately one inch thick, and the ball core. Ideally, for the sake of bowling accuracy, interaction between the hole defining surface of the ball and a finger should remain constant to assure consistent ball release. In actuality however, such interaction is not constant because: (1) A bowling ball may be of other than homogeneous construction formed from two or more constituent materials; (2) A professional or serious amateur bowler may own several balls to best suit specific lane conditions which balls may be of hard rubber or polyester resin, each type having different finger and ball interaction and hence distinct "release" characteristics; (3) The fingers may swell somewhat after bowling a length of time to alter fit and subsequent ball release.
It is to be noted that the greatest force applied to the ball hole walls is by the distal or outermost phalanges of the three fingers normally used in bowling. Secure engagement of these phalanges with the hole walls assures ball retention until desired release to thereby avoid ball dropping or at least premature release. Once ball release is initiated however it is highly desirable that it be effected rapidly with a minimum of drag on the hole walls by the departing fingers and particularly the thumb.
Previous efforts to enhance finger-to-ball contact have included the provision of strip-like inserts, insertable lengthwise, for adherence to a lengthwise segment of the hole wall. Additionally proposed have been tube-like inserts having a continuous inner wall which, in some instances, the cross sectional area may be mechanically altered for finger fit. Examples of the latter inserts are found in U.S. Pat. Nos. 3,416,796; 3,148,881; 3,004,762. Also old in the art is a tubular insert of resilient material per U.S. Pat. No. 2,273,199. Further U.S. Pat. Nos. 3,454,440 and 3,316,588 show it to be old to form a rigid insert to generally correspond in shape to the fingers. The latter patent discloses an internally contoured insert of homogeneous construction. U.S. Pat. Nos. 2,842,367 and 3,012,783 disclose assembled finger grip inserts wherein an inner sleeve member extends substantially the length of the insert.